Method for comprehensively detecting turn-to-turn short circuit fault of generator stator
By building a fault detection circuit, using UR devices and flexible logic equations, the rapid accuracy of short-circuit fault detection between stator turns of generators is solved, and efficient protection of generators and early fault judgments are achieved.
Patent Information
- Application Number
- CN202411991584.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-11
AI Technical Summary
The prior art is difficult to detect short circuit faults between stator turns quickly and accurately in generators, affecting the protection effect of generators.
Build a fault detection circuit, including external circuits and digital circuits, convert signals through the UR device, edit flexible logic equations, and set user-defined logic to determine the fault of stator turn short circuit after the generator is connected to the grid, and trigger the trip logic between turns protection action.
It realizes the rapid and accurate response of the internal fault condition of the stator after the generator is started and forward in the critical stage, and correctly distinguishes the fault position when the unit is running, providing technical support for early fault judgment.
Smart Images
Figure CN119805216A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of generators, and in particular to a method for omnidirectionally detecting a generator stator turn-to-turn short-circuit fault. Background Art
[0002] In recent years, with the attention of the state, the power industry has also put forward higher requirements for the accuracy, speed and reliability of relay protection. Generators are the core equipment of the power system, and stator turn short circuit is a common fault of generators. It is particularly important to provide timely and accurate protection for generator stator turn short circuit faults. Summary of the invention
[0003] In order to solve the above technical problems, the present invention provides a method for omnidirectionally detecting stator turn-to-turn short-circuit faults of a generator. The method for omnidirectionally detecting a generator stator turn-to-turn short-circuit fault according to the present invention comprises the following steps: (1) Building a fault detection circuit, wherein the fault detection circuit includes an external loop and a digital circuit; (2) converting a UR digital input signal of a UR device in the digital circuit into a digital logic signal; (3) The digital logic signal is ANDed with the zero-sequence voltage analog value of the PT dedicated to the generator inter-turn protection, and edited into a flexible logic equation, and a user-defined logic is set, and the user-defined logic is used as the fault judgment basis for the stator inter-turn short circuit after the generator is excited before the grid connection; (4) The generator terminal voltage and neutral point current analog input signals are ANDed with the generator interturn protection dedicated PT zero-sequence voltage analog input signal to trigger the interturn protection tripping logic, thereby realizing the identification of generator internal faults and interturn faults during normal operation of the unit.
[0004] Furthermore, in step (1), the external circuit includes a generator output circuit breaker, and a hard wiring is provided at the auxiliary contact point of the generator output circuit breaker, and a hard contact is formed, and the hard contact is connected to the UR device contact input digital signal terminal, and converted into a digital logic signal through the UR.
[0005] Furthermore, in step (2), a flexible logic equation is edited to AND the logic signal of the auxiliary contact of the generator output circuit breaker with the analog value of the zero-sequence voltage of the PT opening dedicated for the generator turn-to-turn protection, and the delay action is performed to trip.
[0006] Furthermore, in step (2), a flexible logic equation is edited to AND the generator terminal voltage and neutral point current analog input signal with the generator inter-turn protection dedicated PT zero-sequence voltage analog input signal, and delay the action to trip.
[0007] Furthermore, the logic equation group obtained after ANDing triggers the data recording to record the measurement parameters before and after the event occurs.
[0008] Compared with the prior art, the present invention has the following beneficial effects: On the one hand, the method adds a circuit breaker auxiliary contact hard wiring in the electrical control circuit, and writes the contact status monitoring into the stator turn-to-turn protection logic program of the method for comprehensively detecting the generator stator turn-to-turn short-circuit fault as the generator grid-connection judgment condition, so as to achieve the purpose of quickly and accurately reflecting the internal fault situation of the generator stator in the critical stage after the generator is excited and moving forward; on the other hand, the negative sequence power supply flow is changed from the generator end to the generator neutral point inside the generator microcomputer protection device, so as to ensure that the fault location can be correctly distinguished when the generator stator turn-to-turn short-circuit fault occurs when the unit is running, providing strong technical support for the early judgment of the fault. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 Schematic diagram of the fault detection circuit of the present invention. DETAILED DESCRIPTION
[0010] The present invention is further described below in conjunction with specific embodiments.
[0011] like Figure 1 As shown, the method for omnidirectionally detecting stator turn-to-turn short-circuit faults of a generator according to the present invention comprises the following steps: (1) Building a fault detection circuit, wherein the fault detection circuit includes an external loop and a digital circuit; (2) converting a UR digital input signal of a UR device in the digital circuit into a digital logic signal; Specifically, the external circuit includes a generator output circuit breaker, and a hard wire is provided at the auxiliary contact point of the generator output circuit breaker, and a hard contact is formed, and the hard contact is connected to the UR device contact input digital signal terminal, and converted into a digital logic signal by the UR (3) The digital logic signal is ANDed with the zero-sequence voltage analog value of the PT dedicated to the generator inter-turn protection, and edited into a flexible logic equation, and a user-defined logic is set, and the user-defined logic is used as the fault judgment basis for the stator inter-turn short circuit after the generator is excited before the grid connection; Among them, edit the flexible logic equation, make the logic signal of the auxiliary contact of the generator output circuit breaker and the analog quantity of the zero-sequence voltage of the PT opening dedicated to the generator turn-to-turn protection, and delay the action to trip; or make the generator terminal voltage and the analog quantity input signal of the neutral point current and the analog quantity input signal of the zero-sequence voltage of the PT dedicated to the generator turn-to-turn protection, and delay the action to trip, and trigger the data recording with the logic equation group obtained after the AND operation to record the measurement parameters before and after the event occurs; (4) The generator terminal voltage and neutral point current analog input signals are ANDed with the generator interturn protection dedicated PT zero-sequence voltage analog input signal to trigger the interturn protection tripping logic, thereby realizing the identification of generator internal faults and interturn faults during normal operation of the unit.
Claims
1. A method for omnidirectionally detecting short-circuit faults of stator turns of generators, characterized in that: The method comprises the following steps: (1) Building a fault detection circuit, wherein the fault detection circuit includes an external loop and a digital circuit; (2) converting a UR digital input signal of a UR device in the digital circuit into a digital logic signal; (3) The digital logic signal is ANDed with the zero-sequence voltage analog value of the PT dedicated to the generator inter-turn protection, and edited into a flexible logic equation, and a user-defined logic is set, and the user-defined logic is used as the fault judgment basis for the stator inter-turn short circuit after the generator is excited before the grid connection; (4) The generator terminal voltage and neutral point current analog input signals are ANDed with the generator interturn protection dedicated PT zero-sequence voltage analog input signal to trigger the interturn protection tripping logic, thereby realizing the identification of generator internal faults and interturn faults during normal operation of the unit.
2. The method for omnidirectionally detecting generator stator turn-to-turn short-circuit faults according to claim 1 is characterized in that: In step (1), the external circuit includes a generator output circuit breaker, and a hard wiring is provided at the auxiliary contact point of the generator output circuit breaker to form a hard contact point, and the hard contact point is connected to the UR device contact input digital signal terminal and converted into a digital logic signal through the UR.
3. The method for omnidirectionally detecting generator stator turn-to-turn short-circuit faults according to claim 1 is characterized in that: In step (3), edit the flexible logic equation, compare the logic signal of the auxiliary contact of the generator output circuit breaker with the analog value of the zero-sequence voltage of the PT opening dedicated for the generator turn-to-turn protection, and delay the action to trip.
4. The method for omnidirectionally detecting generator stator turn-to-turn short-circuit faults according to claim 1 is characterized in that: In step (3), edit the flexible logic equation to AND the generator terminal voltage and neutral point current analog input signal with the generator inter-turn protection dedicated PT zero-sequence voltage analog input signal, and delay the action to trip.
5. The method for omnidirectionally detecting generator stator turn-to-turn short-circuit faults according to claim 3 or 4, characterized in that: The logical equation group obtained after ANDing triggers the data recorder to record the measurement parameters before and after the event occurs.